[{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999},{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}] 這種是正確的json對象數組，["{"cardName":"bankCard1","cardCode":"888888888","cardValue":99999999}","{"cardName":"bankCard2","cardCode":"999999999","cardValue":222222222}"]，這種是json字符串數組。

package com.doit8.test.jsontest.pojo; import java.util.ArrayList; import java.util.List; public class Person {   private String username;   private String email;   private String sex;   private int age;   private List<Card> cardList=new ArrayList<Card>();   public String getUsername() {     return username;   }   public void setUsername(String username) {     this.username = username;   }   public String getEmail() {     return email;   }   public void setEmail(String email) {     this.email = email;   }   public String getSex() {     return sex;   }   public void setSex(String sex) {     this.sex = sex;   }   public int getAge() {     return age;   }   public void setAge(int age) {     this.age = age;   }   public List<Card> getCardList() {     return cardList;   }   public void setCardList(List<Card> cardList) {     this.cardList = cardList;   } }

package com.doit8.test.jsontest.pojo; public class Card {   private String cardName;   private String cardCode;   private Integer cardValue;   public String getCardName() {     return cardName;   }   public void setCardName(String cardName) {     this.cardName = cardName;   }   public String getCardCode() {     return cardCode;   }   public void setCardCode(String cardCode) {     this.cardCode = cardCode;   }   public Integer getCardValue() {     return cardValue;   }   public void setCardValue(Integer cardValue) {     this.cardValue = cardValue;   } }

package com.doit8.test.jsontest;  import java.util.ArrayList; import java.util.List; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONArray; import com.alibaba.fastjson.JSONObject; import com.doit8.test.jsontest.pojo.Card; import com.doit8.test.jsontest.pojo.Person; /** * JSON轉換 * */ public class App  {   public static void main( String[] args )   {     //1。通過對象生成JSON串，對象里包含對象數組轉成JSON串。     Person person=new Person();     person.setUsername("xiejava");     person.setSex("man");     person.setAge(38);     person.setEmail("xiejava@ishareread.com");     Card card1=new Card();     card1.setCardName("bankCard1");     card1.setCardCode("888888888");     card1.setCardValue(99999999);     Card card2=new Card();     card2.setCardName("bankCard1");     card2.setCardCode("999999999");     card2.setCardValue(222222222);     //對象數組     List<Card> cards=new ArrayList<Card>();     cards.add(card1);     cards.add(card2);     person.setCardList(cards);     String json = JSON.toJSON(person).toString();     System.out.println(json);     //2.通過JSON對象生成JSON串     JSONObject jObject=new JSONObject();     jObject.put("username", "xiejava");     jObject.put("sex", "man");     jObject.put("age", 38);     jObject.put("email", "xiejava@ishareread.com");     //通過JSONArray包裝對象數組     JSONArray jArray=new JSONArray();     jArray.addAll(cards);     jObject.put("cardList", jArray);     String json2=jObject.toJSONString();     System.out.println(json2);     //3.通過JSON對象生成JSON串     JSONObject jObject2=new JSONObject();     jObject2.put("username", "xiejava");     jObject2.put("sex", "man");     jObject2.put("age", 38);     jObject2.put("email", "xiejava@ishareread.com");     //構造JSON字符串     String cardjsonStr1="{/"cardName/":/"bankCard1/",/"cardCode/":/"888888888/",/"cardValue/":99999999}";     String cardjsonStr2="{/"cardName/":/"bankCard2/",/"cardCode/":/"999999999/",/"cardValue/":222222222}";     JSON.parseObject(cardjsonStr1);     JSONArray jArray2=new JSONArray();     //將JSON字符串轉成JSON對象，加入到JSONArray，[注意一定要用JSON.parseObject()方法轉換成JSON對象，否則還是字符串，轉成JSON串的時候會帶雙引號。]     jArray2.add(JSON.parseObject(cardjsonStr1));     jArray2.add(JSON.parseObject(cardjsonStr2));     jObject2.put("cardList", jArray2);     String json3=jObject2.toJSONString();     System.out.println(json3);   } }

<dependency>   <groupId>com.alibaba</groupId>   <artifactId>fastjson</artifactId>   <version>1.2.15</version> </dependency>